While BPSA advocates on behalf of US industry suppliers in many ways, what we classically think of as advocacy, getting more facilities built and encouraging riders to use them, is spearheaded by other organizations.

People for Bikes:
Formerly Bikes Belong, this organization has done a brilliant job of getting more people on bikes more often by collecting dues from US industry companies and spending those dollars wisely to get new bike facilities built:

International Mountain Bicycling Association (IMBA):
People for Bikes’ counterpart on the mountain trail side of the industry, with 30,000 dues-paying consumer members along with industry company support:

League of American Bicyclists:
For generations past and to come, THE LEAGUE represents bicyclists in the movement to create
 safer roads, stronger communities, and a bicycle-friendly America.

Alliance for Biking and Walking:
Their mission is to create, strengthen, and unite state and local bicycle and pedestrian advocacy organizations throughout North America.